Fluorine-containing halides represented by chemical formulae RflBr, RflI and RflCl, wherein Rfl is a saturated or unsaturated fluorine-containing group, are compounds useful as the intermediates for chemicals, pharmaceuticals, agrochemicals, resins and the like. For example, fluorine-containing saturated alkyl bromides are used as blood substitutes, perfluoroalkylating agents and the like. Fluorine-containing unsaturated bromides, fluorine-containing unsaturated iodides and the like are also useful as monomer components for the production of functional materials, because they have replaceable bromine or iodine as a functional group.
A method for producing a fluorine-containing halide is known which converts a sulfonyl chloride represented by chemical formula RflSO2Cl to a fluorine-containing bromide represented by chemical formula RflBr, in accordance with reaction formula 1 shown below (see, for example, Patent Document 1 listed below):

This method, however, employs HBr, a corrosive gas, at high pressures, and produces as a byproduct HCl, which is similarly a corrosive gas, thus causing corrosion of the reaction vessel. Moreover, the reaction has to be carried out in the absence of water, making it difficult to handle reagents. In addition, the reaction needs to be carried out in a high temperature ranging from about 90 to about 150° C.
Another method is known which produces RflBr in accordance with reaction formula 2 shown below (see Patent Document 2 listed below):RflSO2Cl+quaternary (ammonium or phosphonium) bromide→RflBr+SO2+quaternary (ammonium or phosphonium) chloride   formula 2
The drawbacks of this method are that the use of an expensive quaternary (ammonium or phosphonium) bromide as a starting material is necessary, and that a large amount of byproduct, i.e., a quaternary (ammonium or phosphonium) chloride, is produced as a waste material.
Moreover, a method is known for synthesizing a fluorine-containing chloride represented by chemical formula RflCl using a sulfonyl chloride represented by chemical formula RflSO2Cl as a starting material, wherein RflCl is produced in accordance with the reaction formula shown below (see Patent Document 3 shown below):

This method, however, is also industrially disadvantageous in that the reaction has to be carried out at a high temperature.
No process is known for synthesizing a fluorine-containing iodide represented by RflI using a sulfonyl chloride represented by chemical formula RflSO2Cl as a starting material.    [Patent Document 1] U.S. Pat. No. 4912269    [Patent Document 2] U.S. Pat. No. 5057633    [Patent Document 3] Journal of Fluorine Chemistry, 25 (1984), 491-504